Archive for the ‘Biology’ Category

Autumnwatch #4: The Comma: Is it a leaf? Is it a form of punctuation? No, it’s a Butterfly!

IMG_0465  Another butterfly that you might catch flying on these sunny Autumn days is the Comma (Polygonia c-album). A member of Nymphalidae, it is drawn to late autumn flowers and fallen fruit. It’s a very interesting species for a number of reasons. Firstly, look at that camouflage! The whole wing shape of the Comma has evolved to look like the shape of a dead leaf; when it closes its wings, all you see are the crinkled brown undersides, a perfect illusion. Even the attractive uppersides are an aesthetically seasonal mix of orange and brown.IMG_0407

GRAMMATICAL BUTTERFLIES?

So why the unusual name? Well, if you look closely in the picture below, you can see a little white mark on the underside of the wings that looks like… a comma. Bizarrely enough, the butterfly has a North American relative called ‘The Question Mark’ that has a white mark that looks a bit like…a question mark! (I challenge you to a cross-curricular link to this preparation for Mr Gove’s SPAG test!)

IMG_0417

Spot the comma…

question-mark-butterfly-with-folded-wings-doris-potter

And spot the question mark on its North American friend..
(Picture source: Fine Art America)

FLUCTUATING POPULATIONS

The Comma is now quite a frequent sight across Britain, but once the situation was very different. At the turn of the century, numbers started a massive decline; by the 1920s there were only a few colonies left in Hereford and Worcestershire. Happily, things suddenly and inexplicably improved, and this species is one of the few butterfly success stories of recent years.

More info and photos here…http://www.ukbutterflies.co.uk/species.php?species=c-album

Advertisements

AUTUMNWATCH #3: MAPLE OR SYCAMORE?

IMG_0677So then, on to identification of some common leaves… Today we’re tackling some species that belong in the same genus and are often confused: the Norway Maple and the sycamore.

In fact, our heading is really a trick question; these are both technically Maples, sharing the genus Acer. They are also relatively common, frequently planted in school grounds, and you are likely to come across them during your Autumn leaf searches.

IMG_0675

Norway Maple

The picture above shows a Norway Maple leaf on the left and a Sycamore leaf on the right. The main difference is that the Norway Maple has a significantly more jagged edge, and a glossier surface. In fact, although not the same species, it looks very similar to the Maple leaf on the Canadian flag. In looking at the full trees, Sycamores also tend to grow higher.

In Autumn, the leaves become much easier to tell apart. Norway Maple leaves are some of the first to change  colour, turning a blazing scarlet that illuminates streets, parks and woodlands. There’s a dark side to this beauty; actuall,y this red pigment is produced as a side-effect of something called allelopathy. This is the scientific name for a sneaky trick the tree has up its sleeve to fend off competition for resources from nearby trees. Norway maples produce and release chemicals to hinder the growth of nearby saplings. The blood-red pigments are merely a by-product of this.

Sycamore leaves never turn red. They usually go a blotchy green-yellow. This sample is also adorned with black spots; rather than a consequence of autrumn colour changes, this is actually a fungus that becomes an increasingly common sight. Although it doesn’t look so nice, and the trees probably aren’t too happy about it, spotting this is actually a positive sign. The fungus can only flourish in very clean air, so it’s a great environmental indicator for air quality.

IMG_0676

Sycamore

(OPAL have some tree health surveys based around this that you can do in your school grounds).

So, in summary; sycamores grow taller, and their leaves turn yellow. Norway maples turn red, are a bit selfish, and have glossier leaves. Both trees share the ‘helicopter’ keys beloved by children and so useful when teaching seed dispersal, so it;s worth getting to know their names.

Before we go, there’s one more maple tree to be mentioned: the Field Maple is smaller and less showy than both of the others. Sometimes it is used as a hedging plant. It’s leaves are smaller and more rounded, and turn yellow rather than red. It too produces ‘helicopter’ keys, but they are much smaller.

Fieldmaple_leavesDC250

Field Maple

Primary Scientists Autumnwatch #1: The Small Tortoiseshell

Well, Autumn hasn’t officially started yet, but here we go! These first few weeks of the Autumn term are interesting ones, the interface between the fading summer and the oncoming crisp golden-ness of October making for some great wildlife-watching  opportunities.

Already the days are starting to have that September chill in the air, and soon the numbers of insects will be diminishing. There are several species of butterfly still to be seen ‘on the wing’ into September and October, and in fact these are some of our most colourful and familiar. Today we are highlighting a well-known and popular species, the Small Tortoiseshell.

—-

THE SMALL TORTOISESHELL

Aglais urticae

IMG_0280

One of the most colourful species of butterfly to be seen in Britain, the Small Tortoisheshell is widespread throughout the country. Partly, this is due to the wide availability of its foodplant, the common stinging nettle. However, in recent years it has become significantly less common, with recent studies citing as high as 52% decreases in some areas. There is some speculation that this is because of the spread of a parasitic fly, Sturmia bella, whose eggs are laid on nettle leaves and then ingested by caterpillars. You can read more about a study into this here.

On the bright side, the butterfly seems to have enjoyed a good summer this year, no doubt boosted by our scorching July!

There are two broods of the species each year. Adults hatch in July and August, and can survive not only our Autumn, but winter as well. Although you probablyt won’t see them, they are one of the few species that hibernate, in sheds, outbuildings and eaves of buildings. On warm February days you might be startled to find one of these overwintering specimens flying around your house, having woken prematurely!

The overwintered Tortoiseshells are some of the first butterflies to be seen each year, and breed again in the Spring.

CLASSROOM POTENTIAL

Small Tortoiseshell caterpillars - coming to a classroom near you?

Small Tortoiseshell caterpillars – coming to a classroom near you?

The Small Tortoishell is a great species to use in class supporting life cycles. Caterpillars are easily bred in captivity, and fresh nettles are easy to find to top up their food supply; it’s a great one to rear in your classroom, and the butterflies can be released anywhere. The organisation WorldWideButterflies provides special school rearing packs (as well as lots more) here, which are available from September. Obviously, this sort of project provides lots of great learning opportunities. As well as purely Science objectives, you could work in literacy themes of explanations (the life cycle), instructions (how to care for the caterpillars), as well as poetry, descriptive writing and so forth. As well as learning opportunities, there is the potential to help boost wild stocks of a species not as common as it was.

EXTINCT RELATIVE

Did you know that the Small Tortoiseshell has a much rarer relative?

The Large Tortoiseshell. Picture source: Wikipedia

The Large Tortoiseshell. Picture source: Wikipedia

The Large Tortoisheshell Nymphalis polychloris, is superficially similar, but a paler orange and, you guessed it, larger. It once lived alongside it’s smaller cousin in the U.K., but has been declared extinct here for a number of years. Partly this was due to its more specialised needs; the caterpillars fed on elm trees, much less common than nettles. It hasn’t been seen for certain since the 1950s, although there are hopes for a comeback in the Isle of Wight.

Exploring Plants

We’ve mentioned plants a lot lately. With the topic coming up in Y1, 2 and 3, it’s important to make sure that lessons don’t get too formulaic, or similar, so that children’s progression and interest are maintained. I thought I’d share some of the work produced by children in a recent Y3 lesson. This could be a starting point for a lesson tackling the new focus on classifying and identifying plants. Giving the children chance to explore and use their prior knowledge about plants gave a good insight into how they needed to progress, rather than simply covering the same ground again. While sorting plants could sound like a fairly dry topic, simple things like having real plants and giving children freedom to explore them can really make a difference.

CHILD-LED INVESTIGATIONS.

We were blessed with a nice day and access to school grounds with a good variety of plants – shrubs, trees, grass and flowers of several different species.

I started the session with the children sat in the circle on the grass, and quickly explained that I wanted them to collect any examples of plants that they could find. It’s a good idea to check beforehand to see if there are any thorny/stinging plants around so that you can warn the kids and set boundaries of areas to avoid.

After they had collected an array of leaves, shoots, seeds and flowers, we went inside. I then gave them free time in groups to sort what they had collected. I left this as an open-ended task – the parameters for grouping were entirely up to the children themselves, giving plenty of opportunities for science talk. The groups they came up with were interesting, often based around tactile adjectives.

plants 003

plants 004

Higher ability groups thought to sort them into groups based on different parts of the plant – flowers, seeds, leaves etc. Interestingly though, even the less scientific groupings tended to be grouped this way by proxy. In the pictures above, for instance, ‘ones that fly’ and ‘rough’ ones, equate to seeds, while leaves are smooth. Seeds and flowers were small, but the leaves collected tended to be bigger. With some thinking time and a few leading questions from me, all the children were able to realise this. This got some good questions flying around: why are seeds rough? Why are they dry? Why are the leaves bigger than the flowers?

MODELLED SORTING

plants 006

The above nicely led us into the fact that there are many different ways of grouping the plant parts, and that they fit into more than one group. I modelled this on the whiteboard, using my plant samples and some double sided sticky tape. The different colour pens show that different samples can belong to different groups, or more than one group. From there, we led into producing dichotomous keys, which start from a simple point and gradually group more specifically.

The children had a go at producing their own keys for their groups. I gave them ID guides for some of the leaves to enable them to write example names in – the example below includes holly and sallow leaves.

plants 009

Even the lowest-achieving children were able to grasp the concept and have a go…

plants 007

Giving the children a chance to explore and find their own examples made them feel like experts. There was plenty of room for scientific talk, ‘working scientifically’ and the opportunity to raise questions for our future learning. They were able to revisit previous knowledge of plant parts, and take this further by classifying and identifying some of the plants. By the end, even the boys who had initially groaned “but plants are boring” were asking what we would be learning about next lesson.

As we continue with our plants lessons in the next couple of weeks, I’ll upload some useful resources such as tree ID guides.

Subject Knowledge Booster – species focus

As well as specific school-orientated resources, we’ve started updating our ‘UK Wildlife’ pages with useful subject knowledge. Over time, lots of different species will be added there. Now and again, some especially useful or interesting examples will be featured on the main blog page, too. With so many ‘classic examples’ of organisms, as dictated by the curriculum or just their preponderance in popular consciousness, we often forget some of the great examples lurking on our own doorsteps and back gardens. Such examples are nice to throw in to remind kids that, for instance, camouflage isn’t just a distant process exclusive to far-away chameleons and polar bears. The fact that there are examples that they might actually be able to go and find can really help to engage them. In addition to the photographs, the species will be featured in fact-files  use these as you wish, for your own reference, to give to children for research tasks, or as a reading comprehension resource.

To kick things off, and to fit in with the new Butterflies 101 page, here’s a nice example of a camouflaged species native to our shores…

 

THE GREEN HAIRSTREAK

Callophrys rubi

BLOG 012

The Green Hairstreak (Callophrys rubi) is often overlooked. Our only majorly green butterfly, it is about the size of a thumbnail. It’s not really rare, although according to Butterfly Conservation, last year’s sodden summer caused numbers to drop 68%. What it is, is easily ignored. In fact, the Green Hairstreak’s camouflage is two-fold. The upper side of its wings are a dingy brown, making it inconspicuous and hard to follow in flight. When it settles, it always keeps its wings closed, the green being a good match for the hawthorn leaves it is fond of perching on. Keen sunbathers, the butterflies tilt themselves toward the sun so that their wings absorb the maximum amount of spring sunshine. As they do so, the iridescence of their wings makes them seem to change from a gold-ish green at one  extreme angle to almost turquoise at the other.

BLOG 015

A charming little butterfly, with its tiny teddy-bear face, you can catch it on heathland and moorland across the country from April to June. The examples below are from the Longshaw moors in Derbyshire.

BLOG 011

Related resources

More information on the Green Hairstreak at the superb Butterfly Conservation-affiliated website Uk Butterflies: http://www.ukbutterflies.co.uk/species.php?species=rubi

Here is an abbreviated factfile that you could use…green hairstreak factfile

Filippa Levemarks Blog

Blogging from my artstudio in Göteborg, Sweden

Considering Birds

My continuing adventures in the natural world

The Dragonfly Woman

Aquatic entomologist with a blogging habit

Beetles In The Bush

Experiences and reflections of a Missouri entomologist